1. Of, relating to, or being in the existing direction of motion, as of a spacecraft: fired posigrade rockets to reduce the craft's velocity.
2. Of relating to, or being an orbit that is in the same direction as the direction of rotation of the body being orbited.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
(Astronautics) astronautics of, relating to, or designating motion in the same direction as the current or normal motion
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014